Previous studies from several laboratories, including the Applicant's, suggest the presence of lung carcinoma type-associated antigens which are absent or present at very low levels in normal tissues and tumors originating in other organs. More precise definition and further study of these antigens is made extremely difficult by the lack of a continuous supply of serologic reagents, each of a single specificity. The purpose of the proposed work is to develop such reagents by applying the potent hybridoma technology to generate continuous cell lines secreting monoclonal antibodies. While primary emphasis will be given to acquiring antibodies reacting with lung carcinoma plasma membrane antigens of the above type, antibodies reacting with similar antigens also present in tumors of other organs and antibodies reacting with unexpected normal differentiation antigens will also be sought. Mice will be immunized with purified lung carcinoma plasma membranes, and their spleen cells fused to a non-secreting mouse myeloma cell line (Sp 2/0 Ag-14) using polyethylene glycol. After growing the fusion products in selective medium in tissue culture, the supernatants of the wells containing the fusion products will be screened for antibody activity against the immunizing tumor by a sensitive solid phase radioimmunoassay. The products of the positive wells will be cloned in semi-solid agarose. Individual clones will be selected, grown in culture, and rescreened against the immunizing tumor; positive clones will be further screened by similar assay against normal lung. Clones with no or very weak activity will continue to be grown in culture and assayed extensively against a variety of tumor and normal tissue substrates using both solid phase radioimmunoassay and indirect immunofluorescence on frozen sections. Cell lines which secrete antibodies recognizing the above types of lung carcinoma antigens will be further propagated and the monoclonal antibodies harvested. The long-term objectives are to utilize such monoclonal antibodies to purify the corresponding antigens and establish sensitive in vitro assays for antigen in blood and bronchial washings, for cellular immunity to antigen, and for further classification of histologic material utilizing immunomicroscopic techniques. It is anticipated that this will eventually lead to improved diagnosis and therapy of human lung cancer.